I've taken some heat in recent years for saying that just about everyone needs to take at least 5,000 IU of vitamin D every day. But almost everyone has a vitamin D deficiency. And the RDA of 600 IU isn't enough to correct the deficiency. And this is important. People who are deficient have more health problems than those who aren't. These problems include immunity issues, heart and memory problems, and cancer. But a new study says a deficiency also causes eye disease.

In this study, researchers gave mice vitamin D to middle-aged mice for 6 weeks. The vitamin lowered the toxic beta amyloid in their eyes and blood vessels. You might know beta amyloid as the protein that accumulates in Alzheimer's disease. But it also collects in your eyes, causing macular degeneration. The animals taking the vitamin D actually got better vision. The vitamin also reduced the number of macrophage cells. These cells are an essential part of your immune defense. But higher numbers can mean unwanted inflammation in your body. And we know inflammation contributes to Alzheimer's and eye disease.

This study was on mice, not humans, so it may not be exactly on point with human macular degeneration. But it illustrates the importance of vitamin D to mammalian health. It also suggests that vitamin D could be useful to prevent the beta amyloid buildup we see in Alzheimer's.

What's interesting is that vitamin D, made by ultraviolet light striking your skin, helps your vision. Having macular degeneration is NOT a reason to stay out of the sun, nor is it a reason to block all UV (with UV blocking glasses) from reaching your eyes. My eye doctor mentor Ed Kondrot, MD, teaches that a lack of UV might be just as harmful to your eyes.

People today spend too much time indoors. God designed us to be in the sun, not inside all the time. If you can't get outdoors, I suggest supplemental vitamin D, perhaps 5,000 IU. I've not seen anyone have problems with that dose of vitamin D, even with long-term use. You can order 5,000 IU tablets by following this link.